using System;

using Org.BouncyCastle.Asn1;

namespace Org.BouncyCastle.Asn1.CryptoPro
{
	public class Gost3410PublicKeyAlgParameters
		: Asn1Encodable
	{
		private DerObjectIdentifier	publicKeyParamSet;
		private DerObjectIdentifier	digestParamSet;
		private DerObjectIdentifier	encryptionParamSet;

		public static Gost3410PublicKeyAlgParameters GetInstance(
			Asn1TaggedObject	obj,
			bool				explicitly)
		{
			return GetInstance(Asn1Sequence.GetInstance(obj, explicitly));
		}

		public static Gost3410PublicKeyAlgParameters GetInstance(
			object obj)
		{
			if (obj == null || obj is Gost3410PublicKeyAlgParameters)
			{
				return (Gost3410PublicKeyAlgParameters) obj;
			}

			if (obj is Asn1Sequence)
			{
				return new Gost3410PublicKeyAlgParameters((Asn1Sequence) obj);
			}

			throw new ArgumentException("Invalid GOST3410Parameter: " + obj.GetType().Name);
		}

		public Gost3410PublicKeyAlgParameters(
			DerObjectIdentifier	publicKeyParamSet,
			DerObjectIdentifier	digestParamSet)
			: this (publicKeyParamSet, digestParamSet, null)
		{
		}

		public Gost3410PublicKeyAlgParameters(
			DerObjectIdentifier  publicKeyParamSet,
			DerObjectIdentifier  digestParamSet,
			DerObjectIdentifier  encryptionParamSet)
		{
			if (publicKeyParamSet == null)
				throw new ArgumentNullException("publicKeyParamSet");
			if (digestParamSet == null)
				throw new ArgumentNullException("digestParamSet");

			this.publicKeyParamSet = publicKeyParamSet;
			this.digestParamSet = digestParamSet;
			this.encryptionParamSet = encryptionParamSet;
		}

		public Gost3410PublicKeyAlgParameters(
			Asn1Sequence seq)
		{
			this.publicKeyParamSet = (DerObjectIdentifier) seq[0];
			this.digestParamSet = (DerObjectIdentifier) seq[1];

			if (seq.Count > 2)
			{
				this.encryptionParamSet = (DerObjectIdentifier) seq[2];
			}
		}

		public DerObjectIdentifier PublicKeyParamSet
		{
			get { return publicKeyParamSet; }
		}

		public DerObjectIdentifier DigestParamSet
		{
			get { return digestParamSet; }
		}

		public DerObjectIdentifier EncryptionParamSet
		{
			get { return encryptionParamSet; }
		}

		public override Asn1Object ToAsn1Object()
		{
			Asn1EncodableVector v = new Asn1EncodableVector(
				publicKeyParamSet, digestParamSet);

			if (encryptionParamSet != null)
			{
				v.Add(encryptionParamSet);
			}

			return new DerSequence(v);
		}
	}
}
